If I am climbing a remote snow-filled couloir deep in the mountains, and a rock breaks loose from the cliff above me, it is reasonable for me to believe that the flying piece of stone is indifferent to my presence as it bounces down the slope – it might brain me by pure chance, but it gains nothing by doing so. I can look at the distribution of similar rocks arrayed on the gentler slope below and verify this randomness. But the case is potentially very different for the teeming horde of microorganisms, invertebrates, and buzzards that would take great pleasure in eating my remains. And if I drink straight from the stream below and ingest Giardia lamblia organisms, it is probably not a coincidence that the resulting frequent bathroom breaks will increase the probability that I make a deposit near open water.
There is a fungus in South America that reproduces by infecting an ant and commandeering it’s nervous system, causing it to perform odd behaviors that are not in the normal ant repertoire, but happen to be especially conducive to the propagation of fungal spores. This sort of relationship has been discovered all over the place – I remember reading about another critter (maybe a fluke) that causes a different species of ant to depart from its customary routine and hang out on the tips of blades of grass, where the ant is likely to be eaten by the sheep whose gut is needed to complete the life cycle of the fluke. These phenomena illustrate the incredible power of evolution – that the chance appearance by mutation of an incidental cause in one species with a marginal effect on another species can be amplified and honed over thousands of generations into the appearance of an ingenious stunt.
In the time since Darwin laid the keel of biology, we have come to understand that the living world is full of replicators that have survived from ancient times to the present by possessing heritable traits that made them slightly better than anyone else around at levering themselves into the next generation. There are a lot of strategies for doing the levering, and one particularly effective one is manipulation – why do the hard work of slithering up a blade of grass, when it might be easier to grab the controls of the body of an ant and make it do the work for you? And this is at least as true of our fellow humans as it is of viruses, fungi, and ants. One theory of why humans are so darn smart is that we evolved high levels of intelligence not to outsmart other species, but to out-manipulate one another – a sort of evolutionary arms race in the direction of cleverness.
An understanding of the evolutionary benefits of manipulation should lead us to a healthy skepticism, especially about the motives of unfamiliar agents. I was thinking about this after a recent discussion of belief, skepticism, and the scientific method, and I realized that the relationship between skepticism and evolution is stronger than I had previously understood. Skepticism is associated with evolution because the discovery of evolution by natural selection is one of the great achievements of the scientific project, and evolution is a major flashpoint in the ongoing turf battle between reason and received tradition. But more fundamentally, a worldview informed by skepticism is a logical conclusion that flows from an understanding of humans as an evolved species.
As much as the nature-documentary view of evolution involves carnivores running down and chomping herbivores, a lot of the evolutionary action has got to be intra-species, and in social animals there’s a tension between manipulation, aggression, and dominance on one side and cooperation for mutual benefit on the other. If manipulation were the whole story, we never would have managed to work together enough to build this amazing computer I’m typing on. Theory shows how pro-social behavior can emerge under suitable conditions, and how it can out-compete ruthlessness. Altruism towards family members is easy to understand, but under the right conditions it can extend further – particularly where living arrangements allow for repeated interaction, and the critters in question (e.g. us) have sufficient intelligence and memory to sort out and recognize the reliable characters from the shifty ones. But these conditions are fragile and limited in scope, and powerful motivations for betrayal are never far beneath the surface. Accordingly, manipulation, loyalty, and betrayal are constant preoccupations among people everywhere, and a perennial staple of fiction.
The principles of evolution offer some guidance about when to suspect manipulation most – especially single-shot interactions (for instance buying a used car far from home) and anonymous settings (e.g. emails from ‘friends’ in Nigeria). But far beyond outright fraud, on average a random person who is trying to make you believe something is far more likely to be doing it for their benefit than for yours. The most obvious example is advertising: the product might be good and it might be shoddy, but the person producing the ad copy probably may not even know – their bonus (and their continued employment) hangs on their ability to get you to open your wallet.
Understanding the incentives that are motivating the people (and other organisms) we interact with is a powerful tool. If your doctor receives 30% of his income in the form of clandestine ‘gifts’ from drug manufacturers, it is reasonable to expect that this will have an impact on his prescribing behavior – whether he admits it to himself or not, you are unlikely to be the beneficiary of that influence. But a flight to ‘alternative’ or ‘holistic’ practice is no refuge – indeed the skeptical worldview is frequently under attack by people who would love to convince potential customers that the scientific establishment are fascist storm troopers, so they can sell more herbs or crystals or whatever type of dubious product they have on offer.
Others are skeptical of skepticism for reasons of iconoclasm – ‘it comports with my self-image as an edgy person to claim that all ways of knowing are equally valid’ – or simply aesthetics and wish-fulfillment: ‘true or not, I am happier believing that powerful forces want me to be beautiful and successful.’ (There may even be a strange evolutionary logic to illogic – if I truly believe that warpaint protects me from arrows, I will surely act with more courage, and in a world of less deadly weapons, the added benefit of banishing fear could conceivably more than compensate for the cost of miscalculations about the effects of pigment on projectiles.) Still others condemn the skeptical stance as heartless and austere; that – even if true – it is too thin and hard a pillow for the average mortal to rest their head on at night, and that ordinary people would be better off believing in comforting fictions. But this is condescending. People can handle unvarnished reality, and they make better decisions when they understand it.
Evolutionary insight brings the realization that the world is jam-packed with finely-tuned organisms that in no way have your best interests in mind – ranging all the way from viruses to used car salesmen. This understanding is very different (and potentially a lot less attractive) than conceptions of a stern but loving God – or a fluffy New Age optimism that the universe cares about you and everything happens for a reason – but it has the virtue of being true.The skeptical view is consistent with our best understanding of how the universe works, and it is of a piece with hard-won, durable, practical knowledge of how matter, energy, and living organisms interact. This same body of knowledge amplified our power (and our environmental impact, alas) a hundredfold by harnessing thermodynamics, cured deadly diseases through detailed knowledge and intricate manipulations of invisible biological machinery, built us microscopes and telescopes that allow us to visualize the stuff of the universe across 20 orders of magnitude, and landed a few lucky dudes temporarily on the moon. And it says that the universe doesn’t care about you, no matter how much you wish it did, and furthermore that many of its living pieces would much rather use you for their own purposes than do you a favor.